In the manufacture of containers, such as glass or plastic bottles and jars, the container typically is formed with a finish having an axis and one or more external threads or beads for securing a closure to the finish. The finish has an open mouth surrounded by an axially facing sealing surface for sealing engagement with a closure applied to the container. Manufacturing anomalies can occur at the container sealing surface, such as a warp or an off-level condition, also known as a cocked sealing surface. A “warp” at the sealing surface generally refers to departure of the sealing surface from a planar configuration. “Off-level” refers to a tilt of the average plane of the sealing surface from an orientation perpendicular to the container axis. Warp and off-level anomalies at the sealing surface can occur in combinations, and can affect the ability of an automatic capping machine to apply a closure to the finish and/or to the ability of the closure to form an effective seal against the sealing surface.